Pastor Aeternus
There was stronger opposition to the draft constitution on the nature of the Church, which at first did not include the question of papal infallibility, but the majority party in the Council, whose position on this matter was much stronger, brought it forward. It was decided to postpone discussion of everything in the draft except infallibility. On 13 July 1870, the section on infallibility was voted on: 451 voted simply in favour (placet), 88 against (non placet), and 62 in favour but on condition of some amendment (placet iuxta modum). This made evident what the final outcome would be, and some 60 members of the opposition left Rome so as not to be associated with approval of the document. The final vote, with a choice only between placet and non placet, was taken on 18 July 1870, with 433 votes in favour and only 2 against defining as a dogma the infallibility of the pope when speaking ex cathedra. The two votes against were cast by Bishop Aloisio Riccio, and Bishop Edward Fitzgerald.
The dogmatic constitution states that the Pope has "full and supreme power of jurisdiction over the whole Church" (chapter 3:9); and that, when he "speaks ex cathedra, that is, when, in the exercise of his office as shepherd and teacher of all Christians, in virtue of his supreme apostolic authority, he defines a doctrine concerning faith or morals to be held by the whole Church, he possesses, by the divine assistance promised to him in blessed Peter, that infallibility which the divine Redeemer willed his Church to enjoy in defining doctrine concerning faith or morals" (chapter 4:9).
None of the bishops who had argued that proclaiming the definition was inopportune refused to accept it. Some Catholics, mainly of German language and largely inspired by the historian Johann Joseph Ignaz von Döllinger (who did not formally join the new group) formed the separate Old Catholic Church in protest.
Read more about this topic: First Vatican Council